In a conventional thin-type elevator hoist apparatus such as the one disclosed in Japanese Patent Laid-Open No. 2000-289954, for example, has provided with a cup-shaped base member open at one side, a main shaft planted within the base member at the center of the bottom wall of the cup, a stationary member winding disposed on the inner circumferential surface of the base member, a cup-shaped member pivotally supported for rotation on the main shaft within the cup-shaped base member, and an armature disposed on the outer circumferential surface of the cup-shaped member in opposition to the stationary member winding to constitute an electric motor portion. A drive sheave is formed on the outer circumferential surface of the cup-shaped member. Also, a brake including a brake shoe for braking disposed in opposition to a brake surface on the inner circumferential surface of the cup-shaped member is provided between the base member and the rotatable cup-shaped member.
The rotatable cup-shaped member and the drive sheave provided thereon are generally covered by the stationary cup-shaped member and the support plate, so that the base member has formed therein an opening portion for allowing the elevator main ropes to pass through the opening portion.
Also, on the outer circumferential cylindrical surface portion of the rotary cup-shaped member, a permanent magnet generator is mounted, and on the inner circumferential surface of the base member opposing to the armature, a stationary element is disposed with a small gap therebetween to define an electric motor together with the armature and the stationary element. Also on the outer circumferential portion of the cup-shaped base member, a support plate which is a brake frame is fastened, which has mounted thereon a brake unit. The brake unit works when a brake arm pivotally supported on the support plate presses the brake shoe against the inner circumferential surface (brake surface) on the cup-shaped member outer circumference portion to apply braking force to the rotation of the rope sheave.
Also, on the main shaft at the radially inner side of the brake unit, a main shaft for an encoder or a shaft with a disc is mounted, thereby to transmit a rotation signal to the encoder mounted on the stationary base member.
The conventional elevator hoist apparatus has the structure as above-described and has the thickness smaller than the elevator hoist apparatus before that. However, as the required torque of the elevator hoist apparatus increases, such thin-type elevator apparatus must have an increased thickness. In an elevator system without machine room, the elevator hoist apparatus is usually disposed in a space between the elevator car in the hoistway and the hoistway wall. However, as the thickness of the elevator hoist apparatus increases, the dead space between the elevator car in the hoistway and the hoistway wall or the space occupied by the hoistway though not utilized is increased. Therefore, the elevator hoist apparatus is required to be made further smaller in the axial dimension (thickness as measured in the direction of rotating axis of the rope sheave).